I've been doing some research and I already have a xs power d3400 under the hood. I am thinking of getting a lithium battery to supplement the d3400. I will be upgrading electrical. Power and ground will now be 3/0 awg class m welding cable. Should supply easy 500amps. Ofcourse big 4 upgrade. Have not upgraded alternator yet as I was researching lithium batteries suffer if charged to quickly. I am currently running around 3k watts rms, with potential to upgrade to around 5k watts rms. Have a few questions. I can safely run the lithium and agm without a battery isolator as that is only if you play your system with car off, I will always have mine running. So all the lithiums on the market right now are very expensive and also some don't have proper specs to not effect the life of battery, say charging below or above certain temp. I was thinking it'd be pretty interesting to run a bank of the 18650 batteries, the same kind they use for vaping, however would this work, how many would I need? How would I hook them up to eachother? Would this be a fire hazard? Are there fail safes in them to keep from exploding? How would I charge them? I just want enough to be another d3400 or two and without the 50lbs of weight. I can't seem to find these answers looking online.